1. Field of the Invention
This invention provides compounds having drug and bio-affecting properties, their pharmaceutical compositions and method of use. In particular, the invention is concerned with indoleoxoacetyl piperazine derivatives. These compounds possess unique antiviral activity, whether used alone or in combination with other antivirals, antiinfectives, immunomodulators or HIV entry inhibitors. More particularly, the present invention relates to the treatment of HIV and AIDS.
2. Background Art
HIV-1 (human immunodeficiency virus-1) infection remains a major medical problem, with an estimated 33.4 million people infected worldwide. Currently available HIV drugs include six nucleoside reverse transcriptase (RT) inhibitors (zidovudine, didanosine, stavudine, lamivudine, zalcitabine and abacavir), three non-nucleoside reverse transcriptase inhibitors (nevirapine, delavirdine and efavirenz) as well as five peptidomimetic protease inhibitors (saquinavir, indinavir, ritonavir, nelfinavir and amprenavir). Each of these drugs can only transiently restrain viral replication if used alone. However, when used in combination, these drugs have a profound effect on disease progression. In fact, significant reductions in death rates among AIDS patients have been recently documented. Despite these results, 30 to 50% of patients ultimately fail combination drug therapies. Insufficient drug potency, non-compliance, restricted tissue penetration and drug-specific limitations within certain cell types (e.g. most nucleoside analogs cannot be phosphorylated in resting cells) may account for the incomplete suppression of sensitive viruses. Furthermore, the high replication rate and rapid turnover of HIV-1 combined with the frequent incorporation of mutations, leads to the appearance of drug-resistant variants and treatment failures when suboptimal drug concentrations are present (Larder and Kemp, Gulick, Morris-Jones, et al, Kuritzkes, Vacca and Condra, Schinazi, et al and Flexner, Ref. 6-12). Therefore, novel anti-HIV agents exhibiting distinct resistance patterns, and favorable pharmacokinetic as well as safety profiles are needed to provide more treatment options.
Currently marketed HIV-1 drugs are dominated by either nucleoside reverse transcriptase inhibitors or peptidomimetic protease inhibitors. Non-nucleoside reverse transcriptase inhibitors have recently gained an increasingly important role in the therapy of HIV infections. At least 30 different classes of NNRTIs have been published in the literature (DeClercq, Ref. 13). Dipyridodiazepinone (nevirapine), benzoxazinone (efavirenz) and bis(heteroaryl) piperazine derivatives (delavirdine) are already approved for clinical use. In addition, several indole derivatives including indole-3-sulfones, piperazino indoles, pyrazino indoles, and 5H-indolo[3,2-b][1,5]benzothiazepine derivatives have been reported as HIV-1 reverse transciptase inhibitors (Greenlee et al, Ref. 1, Williams et al, Ref. 2, Romero et al, Ref. 3, Font et al, Ref. 14, Romero et al, Ref. 15, Young et al, Ref. 16, Genin et al, Ref. 17, and Silvestri et al, Ref. 18). Indole 2-carboxamides have also been described as inhibitors of cell adhesion and HIV infection (Boschelli et al. in U.S. Pat. No. 5,424,329, Ref. 4). Finally, 3-substituted indole natural products (Semicochliodinol A and B, didemethylasterriquinone and isocochliodinol) were disclosed as inhibitors of HIV-1 protease (Fredenhagen et al, Ref. 19). However, nothing in these references can be construed to disclose or suggest the novel compounds of this invention and their use to inhibit antiviral infection, including HIV infection.
Structurally related compounds have been disclosed previously (Brewster et al, Ref. 20, Archibald et al, Ref. 21, American Home Products in GB 1126245, Ref. 5). However, the structures differ from those claimed herein in that they are symmetrical bis(3-indolylglyoxamides) rather than unsymmetrical aroyl indoleoxoacetyl piperazine derivatives, and there is no mention of use for treating antiviral infections. Interestingly, the indole moiety present in the compounds disclosed here is the common feature of many non-nucleoside HIV-1 reverse transcriptase inhibitors including Delavirdine from Upjohn (Dueweke et al. 1992, 1993, Ref. 22 and 23).
Additionally, the following compounds are available commercially but have not been reported as being useful as pharmaceuticals, and more specifically for antiviral use in mammals.
Compound LJ952 (available from Menai Organics Ltd., Gwynedd, North Wales): 
Compound TRI-29586 (available from Tripos): 
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It has now been surprisingly found that compounds of formula I, or pharmaceutically acceptable salts thereof, are effective antiviral agents, particularly for treating HIV, whether used alone or in combination with other antivirals, antiinfectives, immunomodulators or HIV entry inhibitors.
The present invention comprises compounds of formula I, or pharmaceutically acceptable salts thereof, 
wherein:
R1, R2, R3, R4 and R5 are each independently H, C1-C6 alkyl, C3-C6 cycloalkyl, C2-C6 alkenyl, C3-C6 cycloalkenyl, C2-C6 alkynyl, halogen, CN, nitro, COOR6 or XR7, each of said alkyl and cycloalkyl being optionally substituted with one to three same or different halogen, amino, OH, CN or NO2;
R6 is H, C1-C6 alkyl, or C3-C6 cycloalkyl, benzyl, each of said alkyl, cycloalkyl and benzyl being optionally substituted with one to three same or different halogen, amino, OH, CN or NO2;
X is O, S or NR6R7;
R7 is H, C1-C6 alkyl, C3-C6 cycloalkyl, C2-C6 alkenyl, C3-C6 cycloalkenyl, C2-C6 alkynyl or C(O)R8, each of said alkyl and cycloalkyl being optionally substituted with one to three same or different halogen, OH, amino, CN or NO2;
R8 is H, C1-C6 alkyl or C3-C6 cycloalkyl;
xe2x80x94Wxe2x80x94 is 
R9, R10, R11, R12, R13, R14, R15, R16, R17, R18, R19, R20, R21, R22 are each independently H, C1-C6 alkyl, C3-C6 cycloalkyl, C2-C6 alkenyl, C3-C6 cycloalkenyl, C2-C6 alkynyl, CR23R24OR25, COR26, COOR27 or C(O)NR28R29, each of said alkyl and cycloalkyl being optionally substituted with one to three same or different halogen, amino, OH, CN or NO2;
R23, R24, R25, R26, R27, R28, R29 are each independently H, C1-C6 alkyl, C3-C6 cycloalkyl, C2-C6 alkenyl, C3-C6 cycloalkenyl or C2-C6 alkynyl;
Ar is a 4-7 membered aromatic ring which may contain one to five heteroatoms independently selected from the group consisting of O, S, N or NR6, wherein said aromatic ring is optionally fused to group B;
B is an aromatic group selected from the group consisiting of phenyl, 1-naphthyl, 2-naphthyl, indenyl, azulenyl, fluorenyl, and anthracenyl; or a heteroaryl group selected from the group consisting of 2-furyl, 3-furyl, 2-thienyl, 3-thienyl, 2-pyridyl, 3-pyridyl, 4-pyridyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, 1,2,3-oxadiazolyl, 1,2,3-triazolyl, 1,3,4-thiadiazolyl, pyridazinyl, pyrimnidinyl, pyrazinyl, 1,3,5-triazinyl, 1,3,5-trithianyl, indolizinyl, indolyl, isoindolyl, 3H-indolyl, indolinyl, benzo[b]furanyl, benzo[b]thiophenyl, 1H-indazolyl, benzimidazolyl, benzthiazolyl, purinyl, 4H-quinolizinyl, quinolinyl, isoquinolinyl, cinnolinyl, phthalazinyl, quinazolinyl, quinoxalinyl, 1,8-naphthyridinyl, pteridinyl, carbazolyl, acridinyl, phenazinyl, phenothiazinyl, and phenoxazinyl;
B and said 4-7 membered aromatic ring may each independently contain one to five substituents which are each independently selected from R30 R31, R32, R33 or R34;
Ra and Rb are each independently H, C1-6 alkyl or phenyl;
Z is 4-methoxyphenyl, 2-pyridyl, 3-pyridyl, 4-pyridyl, pyrazyl, quinolyl, 3,5-dimethylisoxazoyl, isoxazoyl, 2-methylthiazoyl, thiazoyl, 2-thienyl, 3-thienyl, or pyrimidyl; and p is 0-2;
R30 R31, R32, R33, and R34 are each independently H, C1-C6 alkyl, C3-C6 cycloalkyl, C2-C6 alkenyl, C3-C6 cycloalkenyl, C2-C6 alkynyl, halogen, CN, nitro, C(O)R35, COXR36, hydroxyl, COOR6, hydroxymethyl, trifluoromethyl, trifluoromethoxy, Oxe2x80x94[(C1-C4)-straight or branched alkyl], O-benzyl, O-phenyl, 1,2-methylenedioxy, OC(O)C1-6 alkyl, SC(O)C1-6 alkyl, S(O)m C1-6 alkyl, S(O)2 NRaRb, amino, carboxyl, O-Z, CH2xe2x80x94(CH2)p-Z, Oxe2x80x94(CH2)p-Z, (CH2)pxe2x80x94O-Z, CHxe2x95x90CH-Z or XR37, each of said alkyl and cycloalkyl being optionally substituted with one to three same or different halogen, amino, OH, CN or NO2;
m is 0-2;
R35 and R36 are each independently H, C1-C6 alkyl or C3-C6 cycloalkyl;
R37 is H, C1-C6 alkyl, C3-C6 cycloalkyl, C2-C6 alkenyl, C3-C6 cycloalkenyl, C2-C6 alkynyl, C(O)R38 or C(O)OR39, each of said alkyl and cycloalkyl being optionally substituted with one to three same or different halogen, amino, OH, CN or NO2;
R38, R39 are each independently H, C1-C6 alkyl or C3-C6 cycloalkyl, each of said alkyl and cycloalkyl being optionally substituted with one to three same or different halogen, amino, OH, CN or NO2; provided R39 is not H;
R40 is (CH2)nxe2x80x94Y, where n is 0-6;
Y is selected from:
(1) H, C1-6 alkyl, C3-6 cycloalkyl, C2-6 alkenyl, C3-6 cycloalkenyl, C2-6 alkynyl, halogen, CN, nitro, Ar, COOR6, COOAr, xe2x80x94CONRaRb, TR6, NRaRb, xe2x80x94NC(O)NRaRb, xe2x80x94OC(O)R6, xe2x80x94C[N(Ra)2]=N-T-Rb, XR6, xe2x80x94C(O)R6, xe2x80x94C(O)Ar, xe2x80x94S(O)Ra or xe2x80x94S(O)2Ra, provided when Y is xe2x80x94S(O)Ra or xe2x80x94S(O)2Ra then Ra is not H; and
(2) a 4-7 membered heterocyclic ring, optionally substituted with R6, which may contain 1-3 heteroatoms selected from the group consisting of O, S, SO, SO2, N, and NR41, wherein R41 is selected from the group consisting of hydrogen, (C1-C4)-straight or branched alkyl, (C2-C4)-straight or branched alkenyl or alkynyl;
T is S or O;
provided R1-R5, R9-R16 and R30-R34 are not all H at the same time and Ar is phenyl; and
provided R1-R5, R9-R16 and R30-R34 are not all H at the same time and Ar is 2-furyl.
Another embodiment of the invention is a pharmaceutical formulation which comprises an antiviral effective amount of a compound of formula I.
Another embodiment of the invention is a pharmaceutical formulation useful for treating infection of HIV which additionally comprises an antiviral effective amount of an AIDS treatment agent selected from the group consisting of:
(a) an AIDS antiviral agent;
(b) an anti-infective agent;
(c) an immunomodulator; and
(d) HIV entry inhibitors.
Another embodiment of the invention is a method for treating mammals infected with a virus (e.g. HIV), comprising administering to said mammal an antiviral effective amount of a compound of formula II, or pharmaceutically acceptable salts thereof, 
wherein:
R1, R2, R3, R4 and R5 are each independently H, C1-C6 alkyl, C3-C6 cycloalkyl, C2-C6 alkenyl, C3-C6 cycloalkenyl, C2-C6 alkynyl, halogen, CN, nitro, COOR6 or XR7, each of said alkyl and cycloalkyl being optionally substituted with one to three same or different halogen, amino, OH, CN or NO2;
R6is H, C1-C6 alkyl, or C3-C6 cycloalkyl, benzyl, each of said alkyl, cycloalkyl and benzyl being optionally substituted with one to three same or different halogen, amino, OH, CN or NO2;
X is O, S or NR6R7;
R7is H, C1-C6 alkyl, C3-C6 cycloalkyl, C2-C6 alkenyl, C3-C6 cycloalkenyl, C2-C6 alkynyl or C(O)R8, each of said alkyl and cycloalkyl being optionally substituted with one to three same or different halogen, OH, amino, CN or NO2;
R8 is H, C1-C6 alkyl or C3-C6 cycloalkyl;
xe2x80x94Wxe2x80x94 is 
R9, R10, R11, R12, R13, R14, R15, R16, R17, R18, R19, R20, R21, R22 are each independently H, C1-C6 alkyl, C3-C6 cycloalkyl, C2-C6 alkenyl, C3-C6 cycloalkenyl, C2-C6 alkynyl, CR23R24OR25, COR26, COOR27 or C(O)NR28R29, each of said alkyl and cycloalkyl being optionally substituted with one to three same or different halogen, amino, OH, CN or NO2;
R23, R24, R25, R26, R27, R28, R29 are each independently H, C1-C6 alkyl, C3-C6 cycloalkyl, C2-C6 alkenyl, C3-C6 cycloalkenyl or C2-C6 alkynyl;
Ar is a 4-7 membered aromatic ring which may contain one to five heteroatoms independently selected from the group consisting of O, S, N or NR6, wherein said aromatic ring is optionally fused to group B;
B is an aromatic group selected from the group consisting of phenyl, 1-naphthyl, 2-naphthyl, indenyl, azulenyl, fluorenyl, and anthracenyl; or a heteroaryl group selected from the group consisting of 2-furyl, 3-furyl, 2-thienyl, 3-thienyl, 2-pyridyl, 3-pyridyl, 4-pyridyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, 1,2,3-oxadiazolyl, 1,2,3-triazolyl, 1,3,4-thiadiazolyl, pyridazinyl, pyrimidinyl, pyrazinyl, 1,3,5-triazinyl, 1,3,5-trithianyl, indolizinyl, indolyl, isoindolyl, 3H-indolyl, indolinyl, benzo[b]furanyl, benzo[b]thiophenyl, 1H-indazolyl, benzimidazolyl, benzthiazolyl, purinyl, 4H-quinolizinyl, quinolinyl, isoquinolinyl, cinnolinyl, phthalazinyl, quinazolinyl, quinoxalinyl, 1,8-naphthyridinyl, pteridinyl, carbazolyl, acridinyl, phenazinyl, phenothiazinyl, and phenoxazinyl;
B and said 4-7 membered aromatic ring may each independently contain one to five substituents which are each independently selected from R3o R31, R32, R33 or R34;
Ra and Rb are each independently H, C1-6 alkyl or phenyl;
Z is 4-methoxyphenyl, 2-pyridyl, 3-pyridyl, 4-pyridyl, pyrazyl, quinolyl, 3,5-dimethylisoxazoyl, isoxazoyl, 2-methylthiazoyl, thiazoyl, 2-thienyl, 3-thienyl, or pyrimidyl; and p is 0-2;
R30 R31, R32, R33, and R34 are each independently H, C1-C6 alkyl, C3-C6 cycloalkyl, C2-C6 alkenyl, C3-C6 cycloalkenyl, C2-C6 alkynyl, halogen, CN, nitro, C(O)R35, COXR36, hydroxyl, COOR6, hydroxymethyl, trifluoromethyl, trifluoromethoxy, Oxe2x80x94[(C1-C4)-straight or branched alkyl], O-benzyl, O-phenyl, 1,2-methylenedioxy, OC(O)C1-6 alkyl, SC(O)C1-6 alkyl, S(O)m C1-6 alkyl, S(O)2 NRaRb, amino, carboxyl, O-Z, CH2xe2x80x94(CH2)p-Z, O-(CH2)p-Z, (CH2)p-O-Z, CHxe2x95x90CH-Z or XR37, each of said alkyl and cycloalkyl being optionally substituted with one to three same or different halogen, amino, OH, CN or NO2;
m is 0-2;
R35 and R36 are each independently H, C1-C6 alkyl or C3-C6 cycloalkyl;
R37 is H, C1-C6 alkyl, C3-C6 cycloalkyl, C2-C6 alkenyl, C3-C6 cydloalkenyl, C2-C6 alkynyl, C(O)R38 or C(O)OR39, each of said alkyl and cycloalkyl being optionally substituted with one to three same or different halogen, amino, OH, CN or NO2;
R38, R39 are each independently H, C1-C6 alkyl or C3-C6 cycloalkyl, each of said alkyl and cycloalkyl being optionally substituted with one to three same or different halogen, amino, OH, CN or NO2; provided R39 is not H;
R40 is (CH2)nxe2x80x94Y, where n is 0-6;
Y is selected from:
(1) H, C1-6alkyl, C3-6 cycloalkyl, C2-6 alkenyl, C3-6 cycloalkenyl, C2-6 alkynyl, halogen, CN, nitro, Ar, COOR6, COOAr, xe2x80x94CONRaRb, TR6, NRaRb, xe2x80x94NC(O)NRaRb, xe2x80x94OC(O)R6, xe2x80x94C[N(Ra)2]=N-T-Rb, XR6, xe2x80x94C(O)R6, xe2x80x94C(O)Ar, xe2x80x94S(O)Ra or S(O)2Ra, provided when Y is xe2x80x94S(O)Ra or xe2x80x94S(O)2Ra then Ra is not H; and
(2) a 4-7 membered heterocyclic ring, optionally substituted with R6, which may contain 1-3 heteroatoms selected from the group consisting of O, S, SO, SO2, N, and NR41, wherein R41 is selected from the group consisting of hydrogen, (C1-C4)-straight or branched alkyl, (C2-C4)-straight or branched alkenyl or alkynyl; and
T is S or O.
In a preferred embodiment, compounds of formula I and II include those where Ar is phenyl, furyl, isoxazolyl, thiophenyl, pyrazolyl, pyridyl, benzofuryl, benzothiophenyl, indolyl, pyrazinyl, thiazolyl, imidazolyl, thiadiazolyl.
Also preferred are compounds of formulas I and II wherein
W is 
R9, R10, R11, R12, R13, R14, and R15 are each H; and
R16 is methyl.
Also preferred are compounds of formulas I and II wherein R2 is H, fluoro or methoxy.
Also preferred are compounds of formulas I and II wherein R1, R3 and R4 are each H.
The synthesis procedures and anti-HIV-1 activities of the novel indoleoxoacetyl piperazine analogs of formula I are summarized below.
Chemistry
The present invention comprises compounds of formula I, their pharmaceutical formulations, and their use in patients suffering from or susceptible to HIV. The compounds of formula I which include pharmaceutically acceptable salts thereof, 
The term xe2x80x9cC1-6 alkylxe2x80x9d as used herein and in the claims (unless the context indicates otherwise) mean straight or branched chain alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, amyl, hexyl and the like. Similarly, xe2x80x9cC2-6 alkenylxe2x80x9d and xe2x80x9cC2-6 alkynylxe2x80x9d include straight or branched chain groups.
The term xe2x80x9cpharmaceutically acceptable saltxe2x80x9d as used herein and in the claims is intended to include nontoxic base addition salts. Suitable salts include those derived from organic and inorganic acids such as, without limitation, hydrochloric acid, hydrobromic acid, phosphoric acid, sulfuric acid, methanesulfonic acid, acetic acid, tartaric acid, lactic acid, sulfinic acid, citric acid, maleic acid, fumaric acid, sorbic acid, aconitic acid, salicylic acid, phthalic acid, and the like.
xe2x80x9cHalogenxe2x80x9d refers to chlorine, bromine, iodine or fluorine.
In the method of the present invention, the term xe2x80x9cantiviral effective amountxe2x80x9d means the total amount of each active component of the method that is sufficient to show a meaningful patient benefit, i.e., healing of acute conditions characterized by inhibition of antiviral infection, including HIV infection. When applied to an individual active ingredient, administered alone, the term refers to that ingredient alone. When applied to a combination, the term refers to combined amounts of the active ingredients that result in the desired antiviral effect, whether administered in combination, serially or simultaneously. The terms xe2x80x9ctreat, treating, treatmentxe2x80x9d as used herein and in the claims means preventing or ameliorating diseases associated with viral infection, including HIV infection.
The present invention is also directed to combinations of the compounds with one or more agents useful in the treatment of AIDS. For example, the compounds of this invention may be effectively administered, whether at periods of pre-exposure and/or post-exposure, in combination with effective amounts of the AIDS antivirals,
Additionally, the compounds of the invention herein may be used in combination with another class of agents for treating AIDS which are called HIV entry inhibitors. Examples of such HIV entry inhibitors are discussed in DRUGS OF THE FUTURE 1999, 24(12), pp. 1355-1362; CELL, Vol. 9, pp. 243-246, Oct. 29, 1999; and DRUG DISCOVERY TODAY, Vol. 5, No. 5, May 2000, pp. 183-194.
It will be understood that the scope of combinations of the compounds of this invention with AIDS antivirals, immunomodulators, anti-infectives, HIV entry inhibitors or vaccines is not limited to the list in the above Table, but includes in principle any combination with any pharmaceutical composition useful for the treatment of AIDS.
Preferred combinations are simultaneous or alternating treatments of with a compound of the present invention and an inhibitor of HIV protease and/or a non-nucleoside inhibitor of HIV reverse transcriptase. An optional fourth component in the combination is a nucleoside inhibitor of HIV reverse transcriptase, such as AZT, 3TC, ddC or ddI. A preferred inhibitor of HIV protease is indinavir, which is the sulfate salt of N-(2(R)-hydroxy-1-(S)-indanyl)-2(R)-phenylmethyl-4-(S)-hydroxy-5-(1-(4-(3-pyridyl-methyl)-2(S)-Nxe2x80x2-(t-butylcarboxamido)-piperazinyl))-pentaneamide ethanolate, and is synthesized according to U.S. Pat. No. 5,413,999. Indinavir is generally administered at a dosage of 800 mg three times a day. Other preferred protease inhibitors are nelfinavir and ritonavir. Another preferred inhibitor of HIV protease is saquinavir which is administered in a dosage of 600 or 1200 mg tid. Preferred non-nucleoside inhibitors of HIV reverse transcriptase include efavirenz. The preparation of ddC, ddI and AZT are also described in EPO 0,484,071. These combinations may have unexpected effects on limiting the spread and degree of infection of HIV. Preferred combinations include those with the following (1) indinavir with efavirenz, and, optionally, AZT and/or 3TC and/or ddI and/or ddC; (2) indinavir, and any of AZT and/or ddI and/or ddC and/or 3TC, in particular, indinavir and AZT and 3TC; (3) stavudine and 3TC and/or zidovudine; (4) zidovudine and lamivudine and 141W94 and 1592U89; (5) zidovudine and lamivudine.
In such combinations the compound of the present invention and other active agents may be administered separately or in conjunction. In addition, the administration of one element may be prior to, concurrent to, or subsequent to the administration of other agent(s).
Procedures for making compounds of formula I are shown in Schemes 1-13, and further exemplified in Tables 5-8. 
Starting indoles 1 (Scheme 1) are known or are readily prepared according to literature procedures, such as those described in Cribble, G. (Ref. 24) or Bantoli et al (Ref. 36). The indoles 1 are treated with oxalyl chloride in either THF (tetrahydrofuran) or ether to afford the desired glyoxyl chlorides 2 according to literature procedures (Lingens, F. et al, Ref. 25). The intermediate glyoxyl chlorides 2 are then coupled with benzoyl piperazine 3 (Desai, M. et al, Ref. 26) under basic conditions to afford 4. 
Treatment of indole-3-glyoxyl chloride 2 (Scheme 2) with tert-butyl 1-piperazinecarboxylate 5 affords the coupled product 6. Deprotection of the Boc group of 6 is effected with 20% (trifluoroacetic acid) TFA/CH2Cl2 to yield 7. This product is then coupled with carboxylic acid in the presence of polymer supported 1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide (P-EDC) to afford products 8. 
For Examples 58-81, piperazine 7 (Scheme 3) was treated with Boc-protected aminobenzoic acid in the presence of EDC to afford 8a. A portion of the resulting product was separated and subjected to TFA in order to remove the Boc group, thus yielding amino derivatives 9. 
For Examples 82-89, piperazine 7 (Scheme 4) was treated with acetoxybenzoic acid in the presence of EDC to afford 8b. A portion of the resulting product was separated and subjected to LiOM hydrolysis in order to remove the acetate group, thus yielding hydroxy derivatives 10.
Examples containing substituted piperazines are prepared using the general procedures outlined in Schemes 5-13.
Substituted piperazines are either commercially available from Aldrich, Co. or prepared according to literature procedures (Behun et al, Ref. 31(a), Scheme 5, eq. 01). Hydrogenation of alkyl substituted pyrazines under 40 to 50 psi pressure in ethanol afforded substituted piperazines. When the substituent was an ester or amide, the pyrazine systems could be partially reduced to the tetrahydropyrazine (Rossen et al, Ref. 31(b), Scheme 5, eq. 02). The carbonyl substituted piperazines could be obtained under the same conditions described above by using commercially available dibenzyl piperazines (Scheme 5, eq. 03). 
2-Trifluoromethylpiperazine (Jenneskens et al., Ref. 31c) was prepared through a four step route (Scheme 6). Using Lewis acid TiCl4, N,Nxe2x80x2-dibenzylethylenediamine 11 reacted with trifluoropyruvates 12 to afford hemiacetal 13, which was reduced at room temperature by Et3SiH in CF3COOH to lactam 14. LiAlH4 treatment then reduced lactam 14 to 1,4-dibenzyl-2-trifluoromethylpiperazine 15. Finally, hydrogenation of compound 15 in HOAc gave the desired product 2-trifluoromethylpiperazine 16. 
Mono-benzoylation of symmetric substituted piperazines could be achieved by using one of the following procedures (Scheme 7). (a) Treatment of a solution of piperazine in acetic acid with acetyl chloride afforded the desired mon-benzoylated piperazine (Desai et al. Ref. 26, Scheme 7, eq. 04). (b) Symmetric piperazines were treated with 2 equivalents of n-butyllithium, followed by the addition of benzoyl chloride at room temperature (Wang et al, Ref. 32, Scheme 7, eq. 05). 
Mono-benzoylation of unsymmetric substituted piperazines could be achieved by using one of the following procedures (Scheme 8), in which all the methods were exemplified by mono-alkyl substituted piperazines. (a) Unsymmetric piperazines were treated with 2 equivalents of n-butyllithium, followed by the addition of benzoyl chloride at room temperature to afford a mixture of two regioisomers, which could be separated by chromatography (Wang et al, Ref. 32 and 33(b), Scheme 8 eq. 06); (b) Benzoic acid was converted to its pentafluorophenyl ester, and then further reaction with 2-alkylpiperazine to provide the mono-benzoylpiperazines with the benzoyl group at the less hindered nitrogen (Adamczyk et al, Ref. 33(a), Scheme 8, eq. 07); (c) A mixture of piperazine and methyl benzoate was treated with dialkylaluminum chloride in methylene chloride for 2-4 days to yield the mono-benzoylpiperazine with the benzoyl group at the less hindered nitrogen (Scheme 8, eq. 08); (d) Unsymmetric piperazines were treated with 2 equivalents of n-butyllithium, followed by subsequent addition of triethylsilyl chloride and benzoyl chloride in THF at room temperature to afford mono-benzoylpiperazines with the benzoyl group at the more hindered nitrogen (Wang et al, Ref. 33(b), Scheme 8, eq. 09). When the substituent at position 2 was a ester or amide, the mono-benzoylation with benzoyl chloride occurred at the less hindered nitrogen of the piperazine with triethylamine as base in THF (Scheme 8, eq. 10). 
In the case of tetrahydropyrazines (Scheme 9, eq. 11), mono-benzoylation occurred at the more hindered nitrogen under the same conditions as those in equation 10 of Scheme 8, in the well precedented manner. (Rossen et al, Ref. 31(b)). 
Furthermore, the ester group can be selectively reduced by NaBH4 in the presence of the benzamide (Masuzawa et al, Ref. 34), which is shown in Scheme 10. 
Hydrolysis of Ester Group to Acid:
The ester groups on either the piperazine linkers or on the indole nucleus could be hydrolyzed to the corresponding acid under basic conditions such as K2CO3 (Scheme 11, eq. 13) or NaOMe (Scheme 11, eq. 14) as bases in MeOH and water. 
Coupling Reaction: 
Reaction of glyoxyl chloride 2 with substituted benzoyl piperazines or tetrahydropyrazines (17) in CH2Cl2 using i-Pr2NEt as base afforded the desired products 18.
In the case of coupling reactions using 3-hydroxylmethylbenzoylpiperazine, the hydroxyl group was temporarily protected as its TMS (trimethylsilyl) ether with BSTFA (N,O-bistrimethylsilyl)fluoroacetamide) (Furber et al, Ref. 35). The unprotected nitrogen atom was then reacted with glyoxyl chlorides 2 to form the desired diamides. During workup, the TMS masking group was removed to give free hydroxylmethylpiperazine diamides 19 (Scheme 13). 
Antiviral Activity
The antiviral activity of the compounds of Examples 1-34 was determined in MT-2 cells (a CD4 positive T-lymphocytic cell line) acutely infected by the BRU strain of HIV-1 in the presence of 10 xcexcM compound. The virus yields were quantitated 6 days after infection using a reverse transcriptase assay (Potts, Ref. 27). The anti-viral results are summarized in Table 1, shown below. Cytotoxicity was determined by incubating cells in the presence of serially diluted compound and cell viability determined using an XTT dye reduction assay (Weislow, Ref. 28). The 50% cytotoxicity concentrations of all compounds were significantly higher than 10 xcexcM, indicating that the compounds are relatively non-toxic.
The antiviral activity of the compounds of Examples 35-215 was determined in HeLa CD4 CCR5 cells infected by single-round infectious HIV-1 reporter virus in the presence of compound at concentrationsxe2x89xa610 xcexcM. The virus infection was quantified 3 days after infection by measuring luciferase expression from integrated viral DNA in the infected cells (Chen et al, Ref. 41). The percent inhibition for each compound was calculated by quantifying the level of luciferase expression in cells infected in the presence of each compound as a percentage of that observed for cells infected in the absence of compound and subtracting such a determined value from 100. Compounds exhibiting anti-viral activity without appreciable toxicity at concentrations xe2x89xa610 xcexcM are presented in Tables 1-4 and 9-13.